1. Field of the Invention
This invention relates to a ratchet driver and more particularly, to a ratchet screwdriver that can accommodate various different heads.
2. Description of the Prior Art
Ratchet screwdrivers are known. However, previous screwdrivers do not function smoothly enough or, they are extremely complex, or they cannot be used to fully tighten a screw, or they employ saw teeth, or, the are dependent on the operation of one or more springs. When saw teeth are used, the screwdriver is often unsafe because of the risk of having a finger caught in the saw teeth. When springs are used, the performance of the driver decreases with the wear of the springs. Slippage can occur in some ratchet screwdrivers if they are used to solidly tighten a screw or to begin to loosen a screw that has already been tightened. Some previous ratchet drivers cannot be readily switched from a clockwise drive position to a counterclockwise drive position. Further, the operation of some previous ratchet screwdriver is so rough that they are too difficult to use for their intended purpose. With many known ratchet screwdrivers, when the handle is turned in the reverse non-driving position relative to the head, there is so much friction between the handle and head that the head cannot easily be prevented from turning and also turns in the reverse direction, thereby causing the screw to turn as well. This can result in little or no progress being made in turning the screw in the appropriate direction. For example, if the screw is turned clockwise in the drive position through 180.degree., when the direction of rotation of the handle is reversed, there is still sufficient friction remaining between the handle and head to cause the screw to turn counterclockwise 180.degree. even though the handle is being turned in a non-drive direction. For any or all of these reasons, ratchet screwdrivers have not attained widespread consumer acceptance and are not widely used.